Small, mobile devices such as hand-held and pocket-sized computers, tablet computers, cellular telephones and the like, are becoming important and popular tools. In general, they have become small enough to be extremely convenient, while consuming less battery power, and at the same time have become capable of running more powerful applications.
Pointing and/or selection devices for entering commands into such mobile devices are currently available in a variety of configurations. Mechanical encoder wheels are often used in various mobile devices as part of the user interface. Many such mechanical encoder wheels include a rotatable wheel or roller mounted on the device. As the wheel is moved, transducers sense the movement of the wheel and generate signals that indicate the direction and amount of the movement. The signals are used, for example, to control movement of a cursor on the screen of the mobile device. The signals may also be used, for example, for scrolling a window that is displayed on the screen in a way that is similar to using the scroll bar of a window to scroll the window.
The shrinking size of mobile devices often entails using smaller pointing devices. However, the smaller features of the smaller input devices commonly result in increased manufacturing difficulties and reliability problems (including increased wear). Manufacturing difficulties typically result in increased cost of manufacturing the mobile devices that comprise the smaller pointing devices. Reliability problems may result in intermittent functionality of the wheel such that, for example, the scrollable window may appear to jump or the wheel may appear to move discontinuously. In more extreme cases, the wheel could fail entirely, which can render the mobile device unusable and require expensive replacement or repair.